Impedance Spectroscopy of Perovskite Solar Cells With SnO2 Embedding Graphene Nanoplatelets

Characterizing the electron transport layer (ETL)/perovskite interface in perovskite solar cells (PSCs) is of paramount importance for their overall performance. In this article the effect of different concentrations of graphene nanoplatelets in addition to SnO 2 is investigated by considering degradation over time. PSCs behavior is monitored by collecting dark current-voltage curves as fabricated and after two months. A deeper insight is gained through impedance spectroscopy analysis. From Nyquist plots equivalent circuit models and the corresponding time constants are extracted. Moreover, resistive part of the impedance associated with high frequency has been related to static shunt resistance, assessing one of the considered ETL doping concentration as the more suitable choice to reduce degradation.